[UI] 플레이어 HUD 및 체력바 개선

- PlayerHUD: HP/MP 바 동기화 개선
- StatBar: 체력바 표시 로직 개선
- Player 프리팹 UI 컴포넌트 설정

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

Assets/Scripts/UI/PlayerHUD.cs

@@ -1,3 +1,4 @@
+using System;
 using UnityEngine;
 using Colosseum.Player;
 
@@ -28,22 +29,26 @@ namespace Colosseum.UI
 
         private void Update()
         {
+            // 플레이어가 아직 없으면 계속 찾기
             if (targetPlayer == null && autoFindPlayer)
             {
                 FindLocalPlayer();
             }
+        }
 
-            if (targetPlayer != null)
-            {
-                UpdateStatBars();
-            }
+        private void OnDestroy()
+        {
+            // 이벤트 구독 해제
+            UnsubscribeFromEvents();
         }
 
         private void FindLocalPlayer()
         {
             var players = FindObjectsByType<PlayerNetworkController>(FindObjectsSortMode.None);
+            Debug.Log($"[PlayerHUD] Finding player... found {players.Length} players");
             foreach (var player in players)
             {
+                Debug.Log($"[PlayerHUD] Player {player.OwnerClientId}: IsOwner={player.IsOwner}, IsSpawned={player.IsSpawned}");
                 if (player.IsOwner)
                 {
                     SetTarget(player);
@@ -57,20 +62,81 @@ namespace Colosseum.UI
         /// </summary>
         public void SetTarget(PlayerNetworkController player)
         {
+            Debug.Log($"[PlayerHUD] SetTarget called: {(player != null ? $"Player {player.OwnerClientId}" : "null")}");
+
+            // 이전 타겟 구독 해제
+            UnsubscribeFromEvents();
+
             targetPlayer = player;
+
+            // 새 타겟 구독
+            SubscribeToEvents();
+
+            // 초기 값 설정
+            UpdateStatBars();
+            
+            Debug.Log($"[PlayerHUD] Initial HP: {targetPlayer?.Health}/{targetPlayer?.MaxHealth}, MP: {targetPlayer?.Mana}/{targetPlayer?.MaxMana}");
+        }
+
+        private void SubscribeToEvents()
+        {
+            if (targetPlayer == null) return;
+
+            targetPlayer.OnHealthChanged += HandleHealthChanged;
+            targetPlayer.OnManaChanged += HandleManaChanged;
+        }
+
+        private void UnsubscribeFromEvents()
+        {
+            if (targetPlayer == null) return;
+
+            targetPlayer.OnHealthChanged -= HandleHealthChanged;
+            targetPlayer.OnManaChanged -= HandleManaChanged;
+        }
+
+        private void HandleHealthChanged(float oldValue, float newValue)
+        {
+            if (healthBar != null && targetPlayer != null)
+            {
+                healthBar.SetValue(newValue, targetPlayer.MaxHealth);
+            }
+        }
+
+        private void HandleManaChanged(float oldValue, float newValue)
+        {
+            if (manaBar != null && targetPlayer != null)
+            {
+                manaBar.SetValue(newValue, targetPlayer.MaxMana);
+            }
         }
 
         private void UpdateStatBars()
         {
+            if (targetPlayer == null)
+            {
+                Debug.Log("[PlayerHUD] UpdateStatBars: targetPlayer is null");
+                return;
+            }
+
+            Debug.Log($"[PlayerHUD] UpdateStatBars: HP={targetPlayer.Health}/{targetPlayer.MaxHealth}, MP={targetPlayer.Mana}/{targetPlayer.MaxMana}");
+
             if (healthBar != null)
             {
                 healthBar.SetValue(targetPlayer.Health, targetPlayer.MaxHealth);
             }
+            else
+            {
+                Debug.LogWarning("[PlayerHUD] healthBar is null!");
+            }
 
             if (manaBar != null)
             {
                 manaBar.SetValue(targetPlayer.Mana, targetPlayer.MaxMana);
             }
+            else
+            {
+                Debug.LogWarning("[PlayerHUD] manaBar is null!");
+            }
         }
     }
 }